Thursday, 22 November 2012

Nerdy Nostalgia

Yeah i know, i probably mean "geek".



Anyway, back in the day, i had a ZX81, almost exactly thirty years ago in fact.  26th November 1982, which if i'm right was a Saturday, my father came back from town with a ZX81 and bought the 16K RAMpack a week later.  My chief memory of that day, oddly, is the new copy of OMNI which had some illustrations inspired by Dougal Dixon's ongoing future evolution project which would eventually become 'Man After Man' - this stuff, which is all copyright and therefore not directly shown:

https://www.google.co.uk/search?q=%22man+after+man%22&hl=en&client=firefox-a&hs=CmW&tbo=u&rls=org.mozilla:en-US:official&tbm=isch&source=univ&sa=X&ei=7BOuUOqaBMqH0AWE8oH4Aw&ved=0CDEQsAQ&biw=1600&bih=797

So a ZX81 then.  A frustrating piece of equipment to be honest, mainly because it was so incredibly slow in almost everything it did, even to some extent in machine code.  What's not often appreciated by people nowadays, if they even know about the machine, is that it was not only slower than the ZX Spectrum, but also slower than its predecessor the ZX80, which also ran four times faster than the Spectrum and was therefore in BBC Micro territory in speed terms.  This ignores the fact that the ZX80 didn't use real numbers.  The reason the ZX81 was so slow is that it multitasked.  Three quarters of its time was normally spent generating the TV picture.

The ZX81 still reminds me a bit of an old-fashioned mainframe hooked up to a teletype, partly because, unusually for the day, it displayed dark characters on a light background and partly because it had an upper case only character set close to that of FORTRAN with the additional pixel and greyscale characters and pound sign:



Unlike a teletype, however, the ZX81 had full cursor control and text and graphics could be displayed anywhere on the screen.  I was initially very confused by the device because i couldn't work out why the characters seemed to display at a much higher resolution than the graphics, and also attempted to "overprint" them, which eventually became a method of faking higher resolution for me when i used machine code to flicker between two characters to make them look like one.

It was quite a test of ingenuity to persuade a ZX81 to do almost anything at all.  At the time, i experienced serious envy of my friends who had cooler computers, although it was at least better than the VIC-20 which was bafflingly awful.

There were also good games available, although at the time i saw games as a guilty pleasure and publicly looked down my nose at them.  One of these was 3-D MONSTER MAZE, which still has the capacity to scare 21st century children used to the likes of The Walking Dead.  Here's a screenshot of the player character after being eaten by the T. rex:



After a couple of years, i moved on to the Jupiter Ace, which as i say in the video is very much a minority computer and in fact Jupiter Cantab was so small it wasn't that much bigger than my own business, Mark's Herbalists, which is really saying something.  The Jupiter Ace was built by some of the people who designed the ZX Spectrum, and looks quite similar.  It even uses the same fonts.  However, unlike the Spectrum and almost uniquely for home micros of the day, it ran FORTH instead of BASIC.  This addressed an issue i used to have with home computers, that they ran a language i sort of felt was for kiddies and not a proper grown-up programming language, and since this appealed to me, just after Jupiter Cantab went bust i went out and bought one, followed fairly soon after by a RAMpack.  The Ace is remarkable in that it can be built from scratch today in exactly the same form as it was originally built, because they couldn't afford to have custom chips built for them.  This also means that my currently broken Ace can in theory be repaired.  Talk about reliability!  This computer is thirty years old now and with a couple of tweaks could be plugged into the right kind of TFT monitor today, book in single-figure seconds with a RAMpack and a fraction of a second without it, and function flawlessly, saving and loading with an MP3 player.  With a shell account and appropriate terminal software, i could even use it to access the web.

Both the ZX81 and the Ace could also be used on Facebook and Twitter with the help of a mobile 'phone alone.  The ZX81 can be used as a web server.  These computers are potentially going concerns and  as someone who veers rapidly off-task i find this horribly enticing.